An Iowa judge is considering sanctioning prosecutors after finding that a federal DEA agent withheld information from the defense about the use of GPS tracking technology to monitor the suspected leader of a drug ring.

U.S. District Judge Mark Bennett ruled last week that DEA investigator David Jensen “acted in bad faith” when he failed to mention GPS tracking in reports detailing the investigation of the suspect.

Bennett said the warrantless GPS tracking of the suspect’s vehicles was legal because agents had reasonable suspicion he was using them in drug trafficking.

The judge said he was “troubled” by Jensen’s concealment and is scheduled to make his decision in court on Thursday, reported the Des Moines Register.

In January, the Supreme Court ruled unanimously that placing a GPS tracking device on a vehicle constitutes a “search” within the definition of the Fourth Amendment and therefore requires a warrant to be constitutional.

Since the Supreme Court’s decision the FBI says it has disabled about 3,000 GPS tracking devices it was using to keep track of suspects’ locations, according to the Wall St. Journal. The FBI disabled the tracking devices in order to comply with the Supreme Court’s recent ruling on warrantless GPS tracking.

The WSJ says FBI General Counsel Andrew Weissmann made the announcement Feb. 23 at a conference titled “Big Brother in the 21st Century.”